Current-diverting guide plate for probe module and probe module using the same

ABSTRACT

A current-diverting guide plate for use in a probe module is disclosed to include a plate body having a first surface, a second surface opposite to the first surface, and a plurality of through holes penetrating through the first and second surfaces. A conducting layer is provided at a periphery wall of each through hole of the plate body and electrically coupled to a probe slidably inserted through the through holes. A current-diverting circuit trace is disposed on the first surface of the plate body and electrically connected with the conducting layers for diverting the electric current flowing through probes. Thus, the current-diverting guide plate can be used to prevent the probes from possible damage due to an excessive instantaneous current.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priorities from Taiwan Patent Application No.102101176 filed on Jan. 11 2013 and Taiwan Patent Application No.102113494 filed on Apr. 16, 2013, the entire contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a probe module for a verticalprobe card and more particularly, to a guide plate for aligning, guidingand supporting probes, which is provided with a current-diverting pathto the probes, and a probe module using the guide plate.

2. Description of the Related Art

FIG. 1 schematically shows a conventional probe module 10 for use in avertical probe card, comprising an upper guide plate 11, namely an upperdie, a lower guide plate 12, namely a lower die, and a plurality ofprobes 13. The probes 13 each have a head 132 inserted through one ofupper guide holes 112 provided at the upper guide plate 11, and a tip134 inserted through one of lower guide holes 122 provided at the lowerguide plate 12. When the tips 134 of the probes 13 contact the contactpads of the device under test (hereinafter referred to as “DUT”), areaction force generated from the DUT is applied to the tips 134 of theprobes 13 and urges the tips 134 of the probes 13 to slidably move backrelative to the lower guide holes 122 to further result in deformationof the bodies 136 of the probes 13. By this mechanism, a stable contactforce acting on the DUT is provided by the tips 134 of the probes 13 forallowing the test signal generated from a tester to be reliablytransmitted to the DUT, and a buffering effect achieved by thedeformation of the bodies 136 of the probes 13 is simultaneouslyprovided upon probing the DUT for protecting the DUT or the probes 13.

In order to meet the product requirements of size reduction andmultifunction, the pitch between two adjacent contact pads of the deviceunder test has become smaller and smaller; under this circumstance, theprobe diameter needs to be minimized for facilitating positive contactof the contact pads of the DUT having a downsized pitch. However, oncethe probe diameter is reduced, the probe 13, especially the bucklingbody 136 of the probe 13, may easily burn out due to an unexpectedexcessive instantaneous current running therethrough. If this happens,the damaged probe 13 has to be repaired or exchanged, causing a delay inthe testing schedule.

To deserve to be mentioned, not only the probe module 10 shown in FIG. 1but also a probe module having a guide plate for aligning, guiding andsupporting the probes, such as the probe modules disclosed in U.S. Pat.No. 4,622,514 and U.S. Pat. No. 7,417,447, may have the above-mentionedproblem, i.e. the slim probe tends to burn out due to instantaneousovercurrent.

SUMMARY OF THE INVENTION

It is one objective of the present invention to provide acurrent-diverting guide plate for a probe module, which enables anelectric current flowing through probes of the probe module to bediverted effectively.

To achieve this objective of the present invention, a current-divertingguide plate comprising a plate body, a plurality of conducting layersand a current-diverting circuit trace is provided by the presentinvention. The plate body has a first surface, a second surface oppositeto the first surface, and a plurality of through holes penetratingthrough the first and second surfaces for slidable insertion of probesof a probe module. Each of the conducting layers is provided at aperiphery wall of one of the through holes of the plate body adapted forbeing electrically coupled to the probe inserting through the associatedthrough hole. The current-diverting circuit trace is disposed on thefirst surface of the plate body and electrically connected with theconducting layers for diverting an electric current flowing through theprobes.

Preferably, the current-diverting circuit trace has a plurality ofprimary branches each connected between two adjacent conducting layersfor providing a primary diverting path.

Preferably, the current-diverting circuit trace further has a pluralityof secondary branches each connected between the two adjacent conductinglayers for providing a secondary diverting path.

Preferably, the conducting layer may be, but not limited to, a compositeconducting layer composed of a metal base layer and a metal coatingcoated on a surface of the metal base layer and containing polymerparticles for reducing friction between the through hole and the probe.

By the above-mentioned technical features of the present invention, thecurrent-diverting guide plate of the present invention thus configuredcan provide a current-diverting path for the electric current flowingthrough the probes, thereby preventing the probes from damage caused byan excessive instantaneous current.

It is another objective of the present invention to provide a probemodule, which uses the aforesaid current-diverting guide plate. Theaforesaid current-diverting guide plate may be applicable to a probemodule equipped with at least one guide plate that is adapted foraligning, guiding, and supporting the probes, such as, but not limitedto, the probe module disclosed in this invention, U.S. Pat. No.4,622,514 or U.S. Pat. No. 7,417,447.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given herein below and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is a schematic drawing of a probe module according to a priorart;

FIG. 2 is a schematic drawing of a current-diverting guide plateaccording to an embodiment of the present invention;

FIG. 3 is an enlarge view of a part of FIG. 2, showing the detailedstructure of the conducting layer;

FIG. 4 is a top view of a part of the current-diverting guide plateaccording to the embodiment of the present invention;

FIG. 5 is a schematic drawing of a probe module using thecurrent-diverting guide plate according to the embodiment of the presentinvention;

FIG. 6 is a schematic drawing of another probe module using thecurrent-diverting guide plate according to the embodiment of the presentinvention; and

FIG. 7 is a schematic drawing of still another probe module using thecurrent-diverting guide plate according to the embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 2 and 4, a current-diverting guide plate 20 providedaccording to an embodiment of the present invention comprises a platebody 30, a plurality of composite conducting layers 40, and acurrent-diverting circuit trace 50. The structural feature of thecurrent-diverting guide plate 20 and the relationship among the elementsof the current-diverting guide plate 20 will be detailed describedhereinafter.

The plate body 30 has a first surface 32, a second surface 34 oppositeto the first surface 32, and a plurality of through holes 36 penetratingthrough the first and second surfaces 32, 34 and each having a circularor square cross-sectional shape. In this invention, the through hole 36has a circular cross section. It is to be understood that the plate body30 may be made from insulated materials, such as ceramic materials,semiconductor materials or conductor materials, such as silicon-basedmaterials. If the plate body 30 is made from the semiconductor materialsor the conductor materials, the surface of the plate body 30 should betreated with insulating coating.

As shown in FIGS. 3 and 5, each of the conducting layers 40 is disposedon a periphery wall of one of the through holes 36 of the plate body 30to define a guide hole 48 for insertion of a probe 22. The conductinglayers 40 each have a metal base layer 42 and a metal coating 44. Bothof the metal base layer 42 and the metal coating 44 may be made of gold,cobalt, nickel, nickel alloys, or any suitable alloy. Further, the metalcoating 44 is coated on the surface of the metal base layer 42 andcontains evenly dispersed polymer particles 46, such aspolytetrafluoroethylene particles, for providing lubrication effect andreducing coefficient of friction.

As shown in FIGS. 2 and 4, the current-diverting circuit trace 50 isdisposed on the first surface 32 of the plate body 30 by a conventionalprocess of making a printed circuit board or other suitable processes. Aplurality of straight primary branches 52 and a plurality of U-shapedsecondary branches 54 are provided by the current-diverting circuittrace 50. Each of the primary branches 52 is electrically connectedbetween two adjacent conducting layers 40 for connecting the conductinglayers 40 in series, such that a primary diverting path P1 is defined bythe primary branches 52; and furthermore, the secondary branches 54 areset side by side and each connected between the two adjacent conductinglayers 40, such that a secondary diverting path P2 is defined by thesecondary branches 54.

FIGS. 2 and 5 show a probe module 60 equipped with two current-divertingguide plates 20 of the present invention. The two current-divertingguide plates 20, namely an upper current-diverting guide plate and alower current-diverting guide plate located below the uppercurrent-diverting guide plate, are spacedly arranged at a distance in amanner that the second surfaces 34 of the plate bodies 30 of the upperand lower current-diverting guide plates 20 face to each other, suchthat the current-diverting circuit traces 50 provided on the firstsurfaces 32 of the plate bodies 30 are exposed outside. By thisarrangement, it is convenient for an engineer to check if there is abreak in the current-diverting circuit traces 50. In alternateembodiment as shown in FIG. 7, the upper and lower current-divertingguide plates 20 are spacedly arranged in a way that the two firstsurfaces 32 of the plate bodies 30 face to each other, such that thecurrent-diverting circuit traces 50 provided on the first surfaces 32 ofthe plate bodies 30 may be well protected.

When the probe module 60 is assembled, the top and bottom ends of eachof the probes 22 are inserted through the corresponding through holes 36of the upper and lower current-diverting guide plates 20. Morespecifically speaking, the top and bottom ends of each probe 22 arerespectively inserted through the corresponding guide holes 48 definedby the conducting layers 40 of the upper and lower current-divertingguide plates 20 and electrically coupled to the conducting layers 40.Once the probes 22 contact the contact pads of a DUT (not shown), theprobes 22 will be moved slidably and smoothly in the guide holes 48 ofthe lower current-diverting guide plate 20 because of the lowcoefficient of friction provided by the composite conducting layers 40,and moreover, the probes 22 will be kept in contact with the conductinglayers 40 when moved up and down in the guide holes 48. Further, asshown in FIGS. 4 and 5, when the probes 22 contact the contact pads ofthe DUT, the electric current passing through the probes 22 will flowfrom the conducting layers 40 to the current-diverting circuit traces 50on the first surfaces 32 of the plate bodies 30, and then the electriccurrent will be diverted by the primary diverting paths P1 defined bythe primary branches 52 of the current-diverting circuit traces 50 andthe secondary diverting paths P2 defined by the secondary branches 54 ofthe current-diverting circuit traces 50. As a result, even if anexcessive instantaneous current is applied to the probes 22, the probes22 will not easily burn out because a current-diverting mechanism isprovided by the present invention, such that the probe diameter can beminimized according to actual needs for getting optimized test results.

However, it is to be mentioned that the probe module can be providedwith one current-diverting guide plate 20 only. As shown in FIG. 6, aprobe module 70 is configured including a current-diverting guide plate20 and a support plate 80 spaced from the current-diverting guide plate20 at a predetermined distance. In this embodiment, the support plate 80provides the function of aligning, guiding, and supporting the probes 22and is not equipped with the conducting layers 40 and thecurrent-diverting circuit trace 50.

Further, the support plate 80 is set above the current-diverting guideplate 20 in this embodiment, but the support plate 80 may be set underthe current-diverting guide plate 20 according to actual needs. In fact,as long as the support plate 80 is arranged facing the second surface 34of the plate body 30 of the current-diverting guide plate 20, the firstsurface 32 of the plate body 30 of the current-diverting guide plate 20will be exposed outside for facilitating check and maintenance of thecurrent-diverting circuit trace 50. In another aspect, the support plate80 may be arranged facing the first surface 32 of the plate body 30 onwhich the current-diverting circuit trace 50 is provided.

When the probe module 70 disclosed in FIG. 6 is assembled, the top endsof the probes 22 are inserted into guide holes 82 of the support plate80 and the bottom ends of the probes 22 are inserted into the guideholes 48 of the current-diverting guide plate 20 and electricallycoupled to the composite conducting layers 40. Thus, when the probes 22contact the contact pads of the DUT, the electric current passingthrough the probes 22 can be diverted by the current-diverting circuittrace 50 of the current-diverting guide plate 20.

To deserve to be mentioned, the conducting layer 40 disclosed in thisinvention is not limited to a composite conducting layer made fromcomposite materials containing the polymer particles 46. A platedthrough hole that is commonly used in printed circuit board can besubstituted for the conducting hole structure produced by the throughhole 36 and the conducting layer 40. In other words, the conductinglayer 40 can be made from a single-layer conducting material that caninclude or exclude the polymer particles 46 as long as the single-layerconducting material is disposed on the periphery wall of one of thethrough holes 36 to define a guide hole for insertion of the probe 22and being electrically connected to the current-diverting circuit trace50. However, the composite conducting layer 40 including the polymerparticles 46 is an optimum choice because of its low coefficient offriction.

On the other hand, the secondary branch 54 is configured to assist theprimary branch 52 in sharing the electric current and provide a backupfunction. In other words, if the primary branch 52 is broken due to amanufacturing defect or long-term use, the secondary branches 54 canstill ensure that the probes 22 are electrically connected with eachother. However, although the secondary branches 54 can be eliminatedaccording to actual needs, the current-diverting circuit trace 50 havingthe secondary branches 54 is an optimum solution that enables the probes22 to withstand a heavy current.

It will be appreciated that the current-diverting guide plate of thepresent invention is basically designed for power probes, which arearranged in an electricity transmitting route of a probe card andadapted for introducing electric power into DUT when the probe card isprobing the DUT. As indicated above, there is a trend that the powerneeded for testing DUT of new generation becomes higher and higher butthe probe diameter needs to become smaller and smaller in testing tasknowadays. In order to resolve the issue of probe burning, this inventionuses the current-diverting guide plate 20 in cooperation with the probes22 (power probes) to realize a current diverting path that can divertthe electric current transmitted from a tester to the DUT.

Finally, it is to be further mentioned that the probe module of thepresent invention is adapted for being utilized in a vertical probecard, and the probes applicable in the present invention may be avertical buckling probes or pogo pins. Since the vertical buckling probehas a buckling or curved body which is usually a weak section that tendsto be firstly burned out upon receiving an instantaneous overcurrent,the current-diverting guide plate of the present invention that has thefunction of diverting instantaneous overcurrent to prevent the probefrom burning out is especially applicable to vertical probe cardadopting the buckling probes to realize maximum effectiveness.

In conclusion, the current-diverting guide plate 20 of the presentinvention uses the composite conducting layers 40 to reduce the frictionbetween the guiding holes 48 and the probes 22 so as to achievesatisfied function of aligning, guiding, and supporting the probes 22.Further, the current-diverting guide plate 20 of the present inventionoffers two different diverting paths P1 and P2 to share the electriccurrent, thereby preventing the probes 22 from damage due to anexcessive instantaneous current.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A probe module comprising: an upper guide plateincluding a plate body that has a first surface, a second surfaceopposite to the first surface, and a plurality of through holespenetrating through the first and second surfaces; a lower guide platespacedly disposed beneath the upper guide plate, the lower guide platecomprising: a plate body having a first surface, a second surfaceopposite to the first surface, and a plurality of through holespenetrating through the first and second surfaces; and acurrent-diverting circuit trace disposed on the first surface of theplate body of the lower guide plate; and a plurality of probes eachslidably inserted through one of the through holes of the plate body ofthe upper guide plate and one of the through holes of the plate body ofthe lower guide plate in a way that the probes each have a probe tipdisposed beneath the lower guide plate and the probes are elasticallydeformable between the upper and lower guide plates when the probe tipscontact a device under test; wherein at least two of the probes areelectrically connected with the current-diverting circuit trace of thelower guide plate; wherein the lower guide plate further comprises aplurality of conducting layers each provided at a periphery wall of oneof the through holes of the plate body of the lower guide plate andelectrically connected with the current-diverting circuit trace of thelower guide plate.
 2. The probe module as claimed in claim 1, whereinthe upper guide plate comprises a current-diverting circuit tracedisposed on the first surface of the plate body of the upper guideplate; the upper guide plate and the lower guide plate are spacedlyarranged in a manner that the two second surfaces of the plate bodies ofthe upper and lower guide plates face to each other; the at least two ofthe probes that are electrically connected with the current-divertingcircuit trace of the lower guide plate are electrically connected withthe current-diverting circuit trace of the upper guide plate.
 3. Theprobe module as claimed in claim 2, wherein the upper guide platefurther comprises a plurality of conducting layers each provided at aperiphery wall of one of the through holes of the plate body of theupper guide plate and electrically connected with the current-divertingcircuit trace of the upper guide plate.
 4. The probe module as claimedin claim 1, wherein the current-diverting circuit trace of the lowerguide plate comprises at least one primary branch connected between twoadjacent said conducting layers.
 5. The probe module as claimed in claim4, wherein the current-diverting circuit trace of the lower guide platecomprises at least one secondary branch connected between the twoadjacent conducting layers.
 6. The probe module as claimed in claim 1,wherein each of the conducting layers of the lower guide plate is acomposite conducting layer comprising a metal base layer and a metalcoating coated on a surface of the metal base layer.
 7. The probe moduleas claimed in claim 6, wherein the metal coating contains polymerparticles.